One type of prior art ink-jet printing system or printing system has a printhead mounted to a carriage which is moved back and forth over print media, such as paper. As the printhead passes over appropriate locations on the print media, a control system activates the printhead to eject ink drops onto the print media and form desired images and characters. To work properly, such printing systems must have a reliable supply of ink for the printhead.
One category of ink-jet printing system uses an ink supply that is mounted to and moves with the carriage. In some types, the ink supply is replaceable separately from the printhead. In others, the printhead and ink supply together form an integral unit that is replaced as a unit once the ink in the ink supply is depleted.
Another category of printing system, referred to as an "off-axis" printing system, uses ink supplies which are not located on the carriage. One type replenishes the printhead intermittently. The printhead will travel to a stationary reservoir periodically for replenishment. Parent application serial number 09/034,874 to this application, entitled "Ink Delivery Systen Adapter", describes another printing system wherein the printhead is fluidically coupled to a replaceable ink supply or container via a conduit such as a flexible tube. This allows the printhead to be continuously replenished during a printing operation.
In a parent application to this application, a replaceable off-axis ink supply is described which has a memory device mounted to the housing. When installed into the printing system, an electrical connection between the printing system and the memory device is established. This electrical connection allows for the exchange of information between the printing system electronics and the memory. The memory device stores information which is utilized by the printing system electronics to ensure high print quality. This information is provided to the printing system electronics automatically when the cartridge is mounted to the printing system. The exchange of information assures compatibility of the cartridge with the printing system.
The stored information further prevents the use of the ink supply after it is depleted of ink. Operating a printing system when the reservoir has been depleted of ink can destroy the printhead. The memory devices concerned with this application are updated with data concerning the amount of ink left in the reservoir as it is being used. When a new cartridge is installed, the printing system will read information from the memory device indicative of the reservoir volume. During usage, the printing system estimates ink usage and updates the memory device to indicate how much ink is left in the cartridge. When the ink is substantially depleted, this type of memory device can store data indicative of an out-of-ink condition. When substantially depleted of ink, these cartridges are typically discarded and a new cartridge along with a new memory device is installed.
Previously used ink containers have fixed volumes of deliverable ink that have been provided for printing systems based generally on ink usage rate requirements of a particular user. However, printing systems users have a wide variety of ink usage rates which may change over time. For ink-jet printing system users who require relatively high ink usage rates, ink containers having these volumes require a relatively high ink container replacement rate. This can be especially disruptive for print jobs which are left to run overnight. Extended continuous use of printing systems causes ink containers to run out of ink during a print job. If the printing system does not shut down during an "ink out" condition, the printhead or the printing system itself may be permanently damaged.
For printing system users who require lower volumes of ink, a different set of problems is encountered if the ink volume is too large. The ink may surpass its shelf life prior to being utilized. Larger ink containers are more expensive and bulkier than smaller cartridges and may be cost prohibitive to small volume users. Thus, a need exists for providing adaptive ink supplies for the ink cartridge described in the parent application, so that ink containers having a variety of ink volumes may be utilized. The adaptive ink supplies should be still able to provide to the printing system the benefits of the memory device of the original equipment ink cartridge.